this book code is achieving the "no indent in 1st para" effect but I cannot suss the mechanism. it has the same styling as other paras. (the added calibre2 style is simply "block")

is it something to do use of new line for 1st line text ( which confusingly seems to have added space at start of line in html) ??

Code:

.....>1. Sorpen</h1>
<p class="western1"><br class="calibre2" />
The level was at his top lip now. Even with his head pressed hard back against the stones of the cell wall his nose was only just above the surface. He wasn't going to get his hands free in time; he was going to drown.</p>
<p class="western1">In the darkness of the cell....

appearance
1. Sorpen

[no indent appears here]The level was at his top lip now. Even with his head pressed hard back against the stones of the cell wall his nose was only just above the surface. He wasn't going to get his hands free in time; he was going to drown.

[1 em indent appears here ]In the darkness of the cell, in its stink and warmth...

Widows and Orphans should prevent that single lines will be on one page or another. In ePub it usually means that that if one line of the paragraph is on the next page, more lines are moved to the next page. There was a thread about that not long ago.

Your problem could be the result of the <br /> inside the same paragraph. If you want a line to appear before the paragraph or after the header, why not solve it with margins? Add a margin-bottom to the <h1> style in CSS or a margin-top to the <p>, perhaps even creating a special class for it, like this:

my "problem " is simply that i don't understand how the no-indent is being achieved with this code. the 1st para style - western1 has 1em indent, yet the 1st line of text appears not indented. that is what I do no understand.

I do know how to do no-indent 1st para in other ways we had a very long thread on the topic recently.- this book seems to use a different solution - that's all.

ok thanks- so 1 simple way to edit a book to remove indents from only 1st paragraphs is to just add <br> at start of each 1st line - that seems much easier than the methods discussed in the previous long thread ?

Only trouble then is there's an extra line of blank space above each paragraph you do it to.
As it's usually first par, it shouldn't matter that much.
As long as you're happy with results, go whichever way you like.

strangely- this formatting method, although fine in epub, does not convert well to mobi - the indent returns! - as it's not a sigil issue I've created a new calibre thread in search of an explanation

Mobi does not support CSS at all and the translations to mobi cannot support this construct. Since mobi does not support it then nothing can be done with conversion issues to fix the problem. And you are right, this has no place in the Sigil forum, or even in the Calibre forum.

sure - but I added it here so that the thread had complete info, in case others followed my lead & then wondered why it did not convert into mobi OK.

I will have to revert to defining a separate non-indent style - that approach converts OK. luckily I'd only tweaked a couple of books using the <br> tag, before noticing the issue.

I find your "mobi does not support CSS" statement misleading.

I'm sure you are technically correct, but it is "supported" in the sense that books can be created/edited in sigil using css styles then converted to mobi in calibre & the styling will carry over into mobi equivalents.

No, the statement is absolutely true. Mobi does not support CSS in any form whatsoever. What's happening is that some of the Mobi creation tools - including Calibre and Mobi Creator - will convert CSS into the equivalent Mobi tag attributes, but that doesn't mean that the resulting Mobi files has CSS: it categorically does not.

well it didn't seem to work for me - viewing the epub ( before) and the mobi ( after) versions with calibre viewer - the epub has no 1st indent but the mobi has. I tried it twice with 2 different books. I initially spotted it after sending book to kindle - I thought maybe I'd messed up conversion or copied an older version so I backtracked & double checked.

building & converting a short test file would prove for definite what is happening